Lake Sibaya Is Narrowly Separated from the LAKE SIBAYA Sea by a Range of High Forested Coastal Dunes
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Lake Sibaya is narrowly separated from the LAKE SIBAYA sea by a range of high forested coastal dunes. The lake is home to large hippopotamus SOUTH AFRICA and crocodile populations, although their numbers have dropped over the last fi fteen 72 years due principally to poaching. The lakeshore is also home to and the drying up of wetlands around the lake raising concerns the only known population of a rare climbing orchid. The yellow among environmentalists. Although Lake Sibaya has been desig- arrows vividly show the increase in cultivation of marginal lands nated a wetland of international importance, there has been little around Lake Sibaya. Agriculture in the lake catchment and along effort by communities around the lake to practice sustainable its drainage lines may cause erosion, eutrophication, pollution, management or to protect the rare species found in the region. 73 Lake Sibaya Lake Sibaya, situated on the coastal plain that makes up north-eastern KwaZulu-Natal in South Africa, is the country’s largest nat- ural freshwater lake, with an area of 60–70 km2 (23–27 square miles). Surface water in the surrounding coastal plain often disap- pears completely during dry years, making the lake the only permanent source of water for mammals and birds. This wetland also supports several of the region’s rural communities, which in many cases are to- tally dependent on its water and associated fl ora and fauna. A Ramsar conservation site, Lake Sibaya is also an important link a particular species of climbing orchid, bers have plummeted by 40 per cent between Kosi Bay and St. Lucia—providing Vanilla roscheri. over the past 15 years, principally due a vital stepping stone for the extension of Although Lake Sibaya has an abun- to poaching. tropical elements down the east coast. dance of coastal resources, it is also suscep- Since 1990, extensive cultivation and The lake system contains the second tible to pollution and siltation due to hu- deforestation in the lake’s catchment area largest population of hippos and croco- man infl uences and the endothecia mosses has increased erosion and eutrophication diles in KwaZulu-Natal, together with 18 that grow around the lake. DDT spraying in most of the drainage lines feeding the species of fi sh, one of which, a freshwater for malaria control in the area is a cause of lake system. Many of the poor local com- goby, is endemic to the system. Twenty-two concern, while more recently interest has munities see logging as a means of improv- species of frogs and eight reptile species been shown in spraying molluscacide in ing their standard of living, leading to the are associated with the lake. Of 279 bird the wetlands to destroy the bilharzia snail injudicious burning of large areas of species recorded in the area, 60 nest and known to carry schistosomiasis . However, forest. There is clearly a growing and breed around the lake. Numerous threat- molluscacide is a poison that is also known urgent need to educate these communi- ened species occur within the lake system, to kill invertebrates and small fi sh (World ties on the sustainable use of their natural including the only known population of Lakes, 2005). Hippo and crocodile num- coastal resources. Schistosomiasis (Bilharzia) Schistosomiasis, also known as bilharzia (bill- HAR-zi-a) or snail fever, is a disease caused by a blood fl uke—a parasite which has a life-cycle split between humans and fresh- water snails. The adult fl ukes, up to 2 cm (0.8 in) long, live inside the blood vessels surrounding the gut or bladder of the hu- man host. Infection occurs when skin comes in contact with contaminated fresh water in which certain types of snails that carry schis- tosomes are living. This fresh water becomes contaminated by Schistosoma eggs when infected people urinate or defecate in the water. The eggs hatch, and if certain types of snails are present in the water, the para- sites grow and develop inside the snails. The parasite leaves the snail and enters the water where it can survive for about 48 hours. Schistosoma parasites then can pen- etrate the skin of persons who are wading, People washing and swimming in a river, a common means of Schistosomiasis transmission from snail to Hans Kylberg/UNEP/Flickr.com swimming, bathing, or washing in contami- human hosts, often with serious health consequences. nated water. The parasites can also enter of scar tissue, dysentery, enlargement of Schistosomiasis is readily treated using a through the lining of mouth or intestinal the spleen and liver, cancer of the bladder, single oral megadose of the drug Praziqu- tract of people who drink untreated water. and cirrhosis of the liver. Some of these antel. While Praziquantel is safe and highly Within several weeks, worms grow inside eggs travel to the bladder or intestines and effective in curing an infected patient, it the blood vessels of the body and produce are passed into the urine or stool. does not prevent re-infection and is not an eggs (MCW 1999). Some 200 million people are thought optimum treatment for people living in en- demic areas. As with other major parasitic The body’s immune system recognises to suffer from this disease in the tropics, and 750 000 people a year die. Schistosomia- diseases, there is ongoing and extensive that the eggs of the fl uke are foreign invad- research into developing a vaccine that will ers and tries to destroy them. The side sis ranks second behind malaria in terms of parasitic diseases and is endemic in 74 prevent the parasite from completing its effects of this powerful immune response life cycle in humans (Wikipedia n.d.). include anaemia, infl ammation, formation developing countries, mostly in Africa. 74 Songor Lagoon The shallow 74 km2 (29 square miles) Son- gor Lagoon is situated to the west of Gha- na’s Volta River estuary, and is one of two large lagoon systems associated with this major river estuary. Comprising a brackish lagoon with extensive mudfl ats and islands, saltpans, a broad sandy beach, and a num- ber of small streams, the open water of the lagoon covers about 11 500 ha and extends about 20 km (12 miles) along the coast and 8 km (5 miles) inland. It is separated from the sea by a narrow sand dune on which several small villages are situated. The lagoon’s importance to birdlife and ma- (Chelonia mydas). Some recreation and the past provided direct connection with rine fauna, including several endangered tourism occurs here, including bird-watch- the Volta River, are effectively blocked. The species of turtle, earned its designation as a ing, turtle-watching, and boating. lagoon has no direct access to the sea and Ramsar protected wetland (Finlayson et al Songor lagoon is the site of an artisanal seawater replenishment is from seepage 2000; Piersma and Ntiamoa-Baidu 1995). salt industry dating back to over a century through the sand-dunes. The main wet- Human activities in and around the and continuously expanding. The lagoon land vegetation-type is saline marsh, with lagoon include farming, fi shing and is also convenient for tourism. Expatriates degraded mangroves (mainly Avicennia sp.) intensive salt extraction. Salt production, and Ghanaians go there for speed boat- and waterlogged grassland along the mar- the main human activity, has led to the ing, recreational fi shing and bird watch- gins of the lagoon, and riverine woodland, extensive modifi cation of the ecosystem ing during weekends and public holidays. scattered thickets of shrubs, climbers and and the reduction of endemic fi sh and About 200 hectares of the Songor lagoon is small trees on higher ground. Terrestrial benthic fauna. As well as many waterbird also suitable for shrimp pond development vegetation away from the lagoon is largely species, the lagoon hosts several globally (Ghana Tourism n.d.). degraded coastal savanna. Human activities in and around the lagoon comprise mainly threatened turtles, including the Leather- The land around the lagoon is low-ly- farming, fi shing and intensive salt extrac- back (Dermochelys coriacea), the Olive Ridley ing, with the highest point less than 10m tion (BirdLife International 2006). (Lepidochelys olivacea), and the Green Turtle (33 ft) above sea-level. Channels, which in A leatherback turtle comes in closer for a better look Unknown/UNEP/Gulf of the Farallones NMS 75 Songor Lagoon is one of the major lagoon SONGOR LAGOON systems, associated with the Volta river estu- ary, with a surface area of about 115 km2 GHANA (44 square miles). These two images show a conspicuous reduction in the surface area 76 of Songor Lagoon—and the environmental health of the wider rainfall variability, closer analysis indicates a more permanent and region. The deep blue open-water area is dramatically reduced signifi cant decline in the lagoon’s surface area. The two main rea- in the 2000 image, with large areas of bare ground exposed. sons for this appear to be salt extraction at the western end of the Although some of these changes may refl ect seasonal or annual lagoon and diversion of feeder streams for irrigation. 77 These two images show the dramatic human- LAKE TONGA induced changes in and around Lake Tonga over the past 15 years. The damming of the ALGERIA feeder rivers of Lakes Tonga and Oubeira 78 (shown in the bottom part of the 2000 im- age) has resulted in increasing irrigation around the dams and a by the construction of dams around Lake Tonga should serve as drastic reduction in the volume of water entering the lake. The an eye-opener to the community.